[PATCH] memory writeback/invalidation fixes

From: "David S. Miller" <davem@redhat.com>

This attempts to take care of 2 of the MM todos I had on
my backlog:

1) Zap the stupid flush_cache_all() thing with more meaningful
   interfaces.

2) Resolve the ptrace user page access issues, first stage.

The "first stage" mentioned for #2 is simply creating the
user page accesor interfaces.  The next stage needs to be
mucking with get_user_pages() so that we can control when
the flush_dcache_page() occurs.  Then we:

1) For every platform where flush_dcache_page() is a non-nop
   add a call to the beginning of copy_{from,to}_user_page().
2) Make access_process_vm() set the "no dcache flush" bit in
   it's call to get_user_pages().

The idea also was that we'd consolidate the write etc. boolean
args passed to get_user_pages() into flag bits too.

But at least with the below, we can delete that reminder FIXME
comment from kernel/ptrace.c, the platforms have the necessary
tools and just need to make use of it :)

As a bonus I noticed that VMALLOC_VMADDR() did absolutely nothing.

After all of this I only have 1 real TODO left, and that's dealing
with the SMP TLB/pte invalidation stuff, very low priority until
someone starts doing more work with sparc32/SMP in 2.6.x :)

1 files changed, 4 insertions, 9 deletions

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index cc3047d5562b..1b68379c4886 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -179,19 +179,14 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in
 
 		flush_cache_page(vma, addr);
 
-		/*
-		 * FIXME!  We used to have flush_page_to_ram() in here, but
-		 * that was wrong.  davem says we need a new per-arch primitive
-		 * to handle this correctly.
-		 */
-
 		maddr = kmap(page);
 		if (write) {
-			memcpy(maddr + offset, buf, bytes);
-			flush_icache_user_range(vma, page, addr, bytes);
+			copy_to_user_page(vma, page, addr,
+					  maddr + offset, buf, bytes);
 			set_page_dirty_lock(page);
 		} else {
-			memcpy(buf, maddr + offset, bytes);
+			copy_from_user_page(vma, page, addr,
+					    buf, maddr + offset, bytes);
 		}
 		kunmap(page);
 		page_cache_release(page);